The Weather Outlook

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Gandalf The White
15 November 2024 10:37:07

Thats a pretty drastic switch. But well expected with these modern era northerlies.

Every thing delayed and shortened.

Originally Posted by: The Dub Version 

I think it just says a lot about the limitations of weather apps which take the raw data from whatever op run they get their numbers.

I think it’s just mid-November today and wintry weather at this stage has always been rare and sustained cold even rarer. It has nothing to do with the ‘modern era’, whatever that is supposed to mean. 🙂


Location: South Cambridgeshire

130 metres ASL

52.0N 0.1E



Gandalf The White
15 November 2024 10:39:03

The switch is far more likely related to the data source being used.

Originally Posted by: Brian Gaze 

Exactly.  I have three weather apps on my phone and they seldom agree beyond a day or two.


Location: South Cambridgeshire

130 metres ASL

52.0N 0.1E



nsrobins
15 November 2024 10:44:47
UKM warnings issued - pretty decent positioning I’d say based on data we see and data we don’t (most of us anyway).

If you’re in the south watch out for later next week - a non zero chance of a major snowfall. If you’re in the north, you have things to contend with from Monday. If you’re far north then boots and scarfs will be required throughout.


Neil

Fareham, Hampshire 28m ASL (near estuary)

Stormchaser, Member TORRO

Brian Gaze
15 November 2024 10:48:34

Today's ECM run is the textbook definition of an omega block.

Fascinating model watching, anyway, and I'll be very interested to see if other models can establish an omega block.

Originally Posted by: Retron 

Here's the extended part of the run.

UserPostedImage


Brian Gaze

Berkhamsted

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Brian Gaze
15 November 2024 10:50:10
Can we stick to the model output in this thread.
Brian Gaze

Berkhamsted

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"I'm not socialist, I know that. I don't believe in sharing my money." - Gary Numan

Rob K
15 November 2024 11:17:51

Thats a pretty drastic switch. But well expected with these modern era northerlies.

Every thing delayed and shortened.

Originally Posted by: The Dub Version 

It certainly seems to be the case that weather models predict things too early - and the change (whether it be to hot or cold) arrives several days later than first modelled.

Anyway the iPhone app certainly doesn;t reflect modelling such as ECM or GEM, or GFS for that matter.

GFS has "forecasting nightmare" all over it at T 180-192, with very heavy rain/sleet/snow

 https://modeles2.meteociel.fr/modeles_gfs/runs/2024111506/186-779UK.GIF?15-6 

https://modeles2.meteociel.fr/modeles_gfs/runs/2024111506/192-779UK.GIF?15-6 

A bit of everything!


Yateley, NE Hampshire, 73m asl

"But who wants to be foretold the weather? It is bad enough when it comes, without our having the misery of knowing about it beforehand." — Jerome K. Jerome

Rob K
15 November 2024 11:24:54
The GFS 6Z is actually really quite bonkers for the south.

Friday 22: daytime max of 3C, heavy snow for a time, turning to rain

Saturday 23, early morning: 14C along the south coast with heavy rain, while just north of the M4 it is barely above freezing! https://modeles2.meteociel.fr/modeles_gfs/runs/2024111506/192-778UK.GIF?15-6 

UserPostedImage

Monday 25 - widely 15C across the south.

Wednesday 27 - back down to freezing with snow!


Yateley, NE Hampshire, 73m asl

"But who wants to be foretold the weather? It is bad enough when it comes, without our having the misery of knowing about it beforehand." — Jerome K. Jerome

doctormog
15 November 2024 11:26:03
There may have been a "drastic switch" in some of the automated apps but there hasn't been a drastic switch in the body of the model output
Sasa
  • Sasa
  • Advanced Member
15 November 2024 11:28:51

It seems to me that the models are struggling with the high-pressure system off Iberia, which is trying to extend its influence further into  Europe. I’ve been monitoring the precipitation forecast for the Alps—it was initially expected to start on Sunday evening, then shifted to Monday, and now it’s been pushed to Tuesday. To my eye, it appears that the models are having difficulty with the setup beyond the 72-hour mark.


Kingston Upon Thames
doctormog
15 November 2024 11:35:35

It seems to me that the models are struggling with the high-pressure system off Iberia, which is trying to extend its influence further into  Europe. I’ve been monitoring the precipitation forecast for the Alps—it was initially expected to start on Sunday evening, then shifted to Monday, and now it’s been pushed to Tuesday. To my eye, it appears that the models are having difficulty with the setup beyond the 72-hour mark.

Originally Posted by: Sasa 

Yes the details are changing and will change on a local (i.e. UK wide not global/hemisphere level) in overall big picture. Such changes while small could have a significant impact on the conditions experienced when the time comes.


Ally Pally Snowman
15 November 2024 11:38:04

The GFS 6Z is actually really quite bonkers for the south.

Friday 22: daytime max of 3C, heavy snow for a time, turning to rain

Saturday 23, early morning: 14C along the south coast with heavy rain, while just north of the M4 it is barely above freezing! https://modeles2.meteociel.fr/modeles_gfs/runs/2024111506/192-778UK.GIF?15-6 

UserPostedImage

Monday 25 - widely 15C across the south.

Wednesday 27 - back down to freezing with snow!

Originally Posted by: Rob K 

That'll be the lying snow. ❄️.

https://www.wetterzentrale.de/en/topkarten.php?map=20&model=gfs&var=25&run=6&time=189&lid=OP&h=0&mv=0&tr=3#mapref 

Also , more than a few hints in the ensembles of the cold spell being extended to the end of November. 


Bishop's Stortford 85m ASL.
Retron
15 November 2024 11:42:41

The GFS 6Z is actually really quite bonkers for the south.

Originally Posted by: Rob K 

And not just in the south - it's bonkers in the far north too. Look at the large area of negative double digits over the Highlands, unusual to see this early in the year. It's a perfect time for it, though... get some snow on the ground and a col and you'll get really low temperatures due to the lack of insolation. By then it's only a month away from the solstice after all!


Leysdown, north Kent
Rob K
15 November 2024 11:43:08
Some notably low overnight temps on the GFS - potential for a date record for 23 November (currently -12.2C)

Edit - yes, you beat me to it Darren. Later on in the run it goes down to -14 to -15 over the Highlands


Yateley, NE Hampshire, 73m asl

"But who wants to be foretold the weather? It is bad enough when it comes, without our having the misery of knowing about it beforehand." — Jerome K. Jerome

Retron
15 November 2024 11:49:53

Some notably low overnight temps on the GFS - potential for a date record for 23 November (currently -12.2C)

Edit - yes, you beat me to it Darren. Later on in the run it goes down to -14 to -15 over the Highlands

Originally Posted by: Rob K 

Great minds and all... 😂

The 0z run was none too warm either. One of the charts I've archived in years gone by is the temp4 one, here:

http://wxmaps.org/pix/temp4.png 

This morning's has two weeks of below zero temperatures over the Highlands. We've not seen that before this early in the year, and it's worth noting!

(The last time it happened was in November 2010, when the charts went from being chilly to exceptionally cold in the space of 3 days - on the 17th it was just looking cold, and by the 20th we had this... it only got colder after that, of course!)

https://ukwct.org.uk/weather/temp4.png 

UserPostedImage


Leysdown, north Kent
Taylor1740
15 November 2024 13:30:23
Looking at the latest GEFS it is now suggesting that it will stay cold for pretty much the rest of November for my area at least albeit with a slight warm up on next week's temperatures.

If correct it will be interesting to see what the CET ends up on as although we've had a warm first half of the month, I think we could still end up sub 6c overall.


NW Leeds - 150m amsl
nsrobins
15 November 2024 16:33:56
Very quiet in here this afternoon. Is it the lull before the storm, the hush before the snow or a general air of resignation that things are not quite going according to plan?

The next best thing to snow is a cold, frosty night and there'll be a few of those next week even if you don't see the white stuff.

Sorry OT.


Neil

Fareham, Hampshire 28m ASL (near estuary)

Stormchaser, Member TORRO

Hippydave
15 November 2024 17:07:36

Very quiet in here this afternoon. Is it the lull before the storm, the hush before the snow or a general air of resignation that things are not quite going according to plan?

The next best thing to snow is a cold, frosty night and there'll be a few of those next week even if you don't see the white stuff.

Sorry OT.

Originally Posted by: nsrobins 

Well the GFS op is rather 'meh' in the medium and long term, although good for low heating bills I guess!

Looking at GEM and GFS at T201 they're very different, so more twists and turns likely. 

One thing to pick out amongst the noise that might be worth watching is the little feature that develops to our NE T80ish and then swings down over Scotland and down England, dying off as it does so. A variant is there on GEM too but if it persists it might bring a surprise or two before it dies away, depending on how much milder air it involves etc. 

I guess other than that it's worth noting Monday/Tuesdays feature is a touch snowier in terms of areas seeing falling snow at least, with a definite back edge effort on this run. The area most at risk of seeing 'proper snow' seems fairly consistent although probably needs another day or so before confidence is high enough to be a bit more definite about snow risk from it.


Home: Tunbridge Wells

Work: Tonbridge

Ally Pally Snowman
15 November 2024 17:08:40
Shite GFS 12z,  but at least GEM is offering hope.

https://www.wetterzentrale.de/en/topkarten.php?map=20&model=gem&var=25&run=12&time=240&lid=OP&h=0&mv=0&tr=12#mapref 


Bishop's Stortford 85m ASL.
Retron
15 November 2024 17:13:07

I guess other than that it's worth noting Monday/Tuesdays feature is a touch snowier in terms of areas seeing falling snow at least, with a definite back edge effort on this run. The area most at risk of seeing 'proper snow' seems fairly consistent although probably needs another day or so before confidence is high enough to be a bit more definite about snow risk from it.

Originally Posted by: Hippydave 

The back edge effect is mentioned in the SE text forecast  from the Met Office, although I'm not sure the wording they've used is quite what you'd expect:

Colder but mainly fine Sunday. Cloudier and windier with some rain Monday, probably giving way to a brighter, colder Tuesday, perhaps with a parting shot of wintry flurries on hills.

If anything it looks like the uncertainty has increased a little here in the south, with the GEFS offering anything from a quick end (as per the op GFS) to a longer block with a Channel low bringing snow, only to be repelled away southwards again.

It is, of course, exactly what we're used to in terms of trying to pin down a cold spell. The only difference really is that we're getting to do it before winter's even started, which is unusual. The areas in the Met Office's warning, i.e. higher ground up north, look much more certain in terms of outlook - there will be snow around, just not necessarily down here.


Leysdown, north Kent
doctormog
15 November 2024 17:14:21

Well the GFS op is rather 'meh' in the medium and long term, although good for low heating bills I guess!

Looking at GEM and GFS at T201 they're very different, so more twists and turns likely. 

Originally Posted by: Hippydave 

Your heating bills maybe. 😛

https://www.wetterzentrale.de/maps/GFSOPUK12_114_48.png 

https://www.wetterzentrale.de/maps/GFSOPUK12_162_48.png 

https://www.wetterzentrale.de/maps/GFSOPUK12_186_48.png 


Chunky Pea
15 November 2024 17:18:23
The longer range EC this morning was holding on to the cooler spell for longer than previous runs. 
Patrick,

East Galway, Ireland.

Jiries
15 November 2024 17:19:31

Heating bills got worst under the HP gloom than unsettled weather that i was using less due to more sun out.  Glad next week no HP so sod off and like those link charts meaning more sunny days as it not under the HP.  Any snow that come here will give lower temps at night.

Chunky Pea
15 November 2024 17:34:29

Heating bills got worst under the HP gloom than unsettled weather that i was using less due to more sun out.  Glad next week no HP so sod off and like those link charts meaning more sunny days as it not under the HP.  Any snow that come here will give lower temps at night.

Originally Posted by: Jiries 

I find that when the sun is out during the dark season that it is colder than when the sky is overcast. There is zero value in it. 


Patrick,

East Galway, Ireland.

Retron
15 November 2024 17:39:53
Incidentally the 12z GEFS control run is keen to prolong the cold, even if the op isn't!
Leysdown, north Kent
Chunky Pea
15 November 2024 17:51:50

Incidentally the 12z GEFS control run is keen to prolong the cold, even if the op isn't!

Originally Posted by: Retron 

GEFS (mean) the same. 


Patrick,

East Galway, Ireland.

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